1. Field of the Invention
The invention is directed to a process of separating clays, for example those containing metal values, from various slurries and aqueous suspensions of such clays by treating them with H.sub.2 S.
2. Discussion of the Prior Art
Sedimentation of clay-containing slimes is conventionally effected by addition of a flocculant, typically an organic polymer. Thus it was surprising to find that contact with H.sub.2 S can have a similar effect. This is important because not only does it provide a way to separate clays, such as phosphate slimes and the like from oggolmerates, but it also indirectly provides a way to gain easier access to metals that are or may be attached to the clay. It should be emphasized that this type of metal removal is not the same as the known H.sub.2 S treatment of certain media to remove metals present in compound form by precipitation as the sulfide. This is known, for example, from U.S. Pat. No. 1,787,192, in which various elements are precipitated from dilute phosphoric acid with H.sub.2 S; U.S. Pat. No. 4,127,639, which discloses the selective precipitation with H.sub.2 S of silver, from aqueous lead solutions obtained by hot chloride leaching of residues containing lead and silver; and Russian Pat. No. 554209, teaching the recovery with H.sub.2 S of alkaline earth metals from sludge arising from aqueous leaching of melts of their metal sulfides.